Method for improving a semiconductor substrate having SiGe film and semiconductor device manufactured by using this method

Abstract

A method of improving a semiconductor substrate including a SiGe film on a Si or SOI substrate is provided. The method includes determining a relationship between a film condition of the SiGe film and a hydrogen ion implantation condition used in making the SiGe film so as to achieve relaxation of lattice distortion in the SiGe film as well as improved crystallinity and/or surface condition of the SiGe film, so that improved conditions for improving quality of the SiGe film on the Si or SOI substrate can be determined.

1. A method of improving a semiconductor substrate including a SiGe film on a Si or SOI substrate, the method including determining a relationship between a film condition of the SiGe film and a hydrogen ion implantation condition used in making the SiGe film so as to achieve relaxation of lattice distortion in the SiGe film as well as improved crystallinity and/or surface condition of the SiGe film, so that improved conditions for improving quality of the SiGe film on the Si or SOI substrate can be determined, the method comprising:
 experimentally determining improvement conditions for making the semiconductor substrate so as to improve relaxation of lattice distortion in the SiGe film and to improve crystallinity and/or surface condition of the SiGe film, by using the following parameters (1), (2) and (3),
 (1) an elastic strain energy U SiGe  which depends on a Ge concentration of the SiGe film and on a thickness of the SiGe film, 
 (2) a peak depth Rp which is a distance between a SiGe/Si interface and a peak position of hydrogen ion concentration in the Si or SOI substrate and which depends on a hydrogen ion implantation energy and on the thickness of the SiGe film, and 
 (3) an amount of hydrogen ions to be implanted; 
 
 determining an amount of hydrogen ions to be implanted and a hydrogen ion implantation energy for the SiGe film based on parameters (1), (2) and (3), and 
 performing the hydrogen ion implantation in the SiGe film based on the determined ion implantation conditions; and 
 wherein the hydrogen ion implantation comprises: 
 (a) calculating elastic strain energy U SiGe  from both the Ge concentration and the thickness of the SiGe film; 
 (b) setting an optional amount of hydrogen ions to be implanted and hydrogen ion implantation energy, respectively; 
 (c) calculating the peak depth Rp from both the thickness of the SiGe film and the set hydrogen ion implantation energy; and 
 (d) determining the amount of hydrogen ions as the parameter (3) and ion implantation energy of hydrogen ions to be implanted, respectively, if the calculated hydrogen ion implantation energy, the calculated the peak depth Rp and the set amount of hydrogen ions to be implanted are in a predetermined range as the experimentally determining improvement conditions by using the parameters (1), (2) and (3). 
 
   
   
     2. The method of  claim 1 , wherein the elastic strain energy U SiGe  is not greater than a normalized value of 0.266. 
   
   
     3. The method of  claim 1 , wherein the amount of hydrogen ions to be implanted is in the range of 2×10 16  to 4×10 16  H + /cm 2 . 
   
   
     4. The method of  claim 1 , wherein the amount of hydrogen ions to be implanted and the hydrogen ion implantation energy for the SiGe film are determined using the elastic strain energy U SiGe  parameter and the parameter of the peak depth parameter Rp when the previously set amount of hydrogen ions to be implanted is 2×10 16 , 3×10 16 , or 4×10 16  H + /cm 2 . 
   
   
     5. The method of  claim 1 , wherein a Si oxide film, a Si nitride film or a Si oxide nitride film is formed as a protection film on the SiGe film. 
   
   
     6. The method of  claim 1 , further comprising carrying out an annealing process in a nitrogen, argon, or hydrogen atmosphere. 
   
   
     7. The method of  claim 1 , wherein the semiconductor device comprises an upper layer semiconductor film including at least one layer, the upper layer semiconductor film being formed on the SiGe film of the semiconductor substrate. 
   
   
     8. The method of  claim 7 , wherein the semiconductor device further includes a top layer semiconductor film formed of a Si film. 
   
   
     9. The method of  claim 8 , wherein the semiconductor device further includes a MOS transistor having a gate oxide film and a gate electrode formed on the top layer semiconductor film and having a source and a drain formed at positions lower than the Si film. 
   
   
     10. A method of making a semiconductor substrate including a SiGe film on a Si or SOI substrate, hydrogen ion implantation be used in making the SiGe film, the method comprising:
 determining an amount of hydrogen ions to be implanted and a hydrogen ion implantation energy for the SiGe film based on parameters (1), (2) and (3), so as to improve relaxation of lattice distortion in the SiGe film and to improve crystallinity and/or surface condition of the SiGe film:
 (1) an elastic strain energy U SiGe  which depends on a Ge concentration of the SiGe film and on a thickness of the SiGe film, 
 (2) a peak depth Rp which is a distance between a SiGe/Si interface and a peak position of hydrogen ion concentration in the Si or SOI substrate and which depends on a hydrogen ion implantation energy and on the thickness of the SiGe film, and 
 (3) an amount of hydrogen ions to be implanted; 
 
 performing the hydrogen ion implantation in the SiGe film based on the determined amount of hydrogen ions to be implanted and the determined ion implantation energy; and 
 wherein the hydrogen ion implantation comprises: 
 (a) calculating elastic strain energy U SiGe  from both the Ge concentration and the thickness of the SiGe film; 
 (b) setting an optional amount of hydrogen ions to be implanted and hydrogen ion implantation energy, respectively; 
 (c) calculating the peak depth Rp from both the thickness of the SiGe film and the set hydrogen ion implantation energy; and 
 (d) determining the amount of hydrogen ions as parameter (3) and ion implantation energy of hydrogen ions to be implanted, respectively, if the calculated hydrogen ion implantation energy, the calculated the peak depth Rp and the set amount of hydrogen ions to be implanted are in a predetermined range as the experimentally determining improvement conditions by using the parameters (1), (2) and (3). 
 
   
   
     11. The method of  claim 10 , wherein the amount of hydrogen ions to be implanted is in the range of 2×10 16  to 4×10 16  H + /cm 2 . 
   
   
     12. The method of  claim 10 , wherein a Si oxide film, a Si nitride film or a Si oxide nitride film is formed as a protection film on the SiGe film. 
   
   
     13. The method of  claim 10 , further comprising carrying out an annealing process in a nitrogen, argon, or hydrogen atmosphere. 
   
   
     14. The method of  claim 10 , wherein the semiconductor device comprises an upper layer semiconductor film including at least one layer, the upper layer semiconductor film being formed on the SiGe film of the semiconductor substrate. 
   
   
     15. The method of  claim 14 , wherein the semiconductor device further includes a top layer semiconductor film formed of a Si film. 
   
   
     16. The method of  claim 15 , wherein the semiconductor device further includes a MOS transistor having a gate oxide film and a gate electrode formed on the top layer semiconductor film and having a source and a drain formed at positions lower than the Si film. 
   
   
     17. The method of  claim 10 , wherein the elastic strain energy U SiGe  is not greater than a normalized value of 0.266. 
   
   
     18. The method of  claim 10 , wherein the range of the improvement conditions is determined by the parameter of the elastic strain energy U SiGe  and the parameter of the peak depth parameter Rp when the previously set amount of hydrogen ions to be implanted is 2×10 16 , 3×10 16 , or 4×10 16  H + /cm 2 .